Polite notice: Intl.js may not be ready for production environments yet. See the status section for more information.

In December 2012, ECMA International published the first edition of Standard ECMA-402, better known as the ECMAScript Internationalization API. This specification provides the framework to bring long overdue localisation methods to ECMAScript implementations.

Google have an implementation of this API that is available in recent versions of V8 and Chrome/Chromium 24 and later. Mozilla also have a working implementation in the current Firefox nightly builds.

Intl.js attempts to fill the void of availability for this API. It will provide the framework as described by the specification, so that developers can take advantage of the native API in environments that support it, or Intl.js for legacy or unsupporting environments.

Status

The latest test, run on Jun 04 2013, scored 99 out of 111 in SpiderMonkey^*. Although the majority of the failed tests are somewhat superficial, there are a few outstanding issues with DateTimeFormat.

Aside from 1 issue with floating point precision in Firefox/SpiderMonkey, NumberFormat seems to be rather complete.

Current progress is as follows:

Implemented

• All internal methods except for some that are implementation dependent
• Checking structural validity of language tags
• Canonicalizing the case and order of language subtags
• Intl.NumberFormat
  • The Intl.NumberFormat constructor (11.1)
  • Properties of the Intl.NumberFormat Constructor (11.2)
  • Properties of the Intl.NumberFormat Prototype Object (11.3)
  • Properties of Intl.NumberFormat Instances(11.4)
• Intl.DateTimeFormat
  • The Intl.DateTimeFormat constructor (12.1)
  • Properties of the Intl.DateTimeFormat Constructor (12.2)
  • Properties of the Intl.DateTimeFormat Prototype Object (12.3)
  • Properties of Intl.DateTimeFormat Instances(12.4)
• Locale Sensitive Functions of the ECMAScript Language Specification
  • Properties of the Number Prototype Object (13.2)
  • Properties of the Date prototype object (13.3)

Not Implemented

• BestFitSupportedLocales internal function
• Implementation-dependent numbering system mappings
• Calendars other than Gregorian
• Collator objects (Intl.Collator) (see below)
• Properties of the String prototype object

A few of the implemented functions may currently be non-conforming and/or incomplete.
Most of those functions have comments marked as 'TODO' in the source code.

^* The test suite is run with Intl.Collator tests removed, and the Collator constructor removed from most other tests in the suite. Also, some of the tests cannot be passed from an ES5 implementation because they check for native behaviour.

What about Intl.Collator?

Providing an Intl.Collator implementation is no longer a goal of this project. There are several reasons, including:

• The CLDR convertor does not automatically convert collation data to JSON
• The Unicode Collation Algorithm is more complicated that originally anticipated, and would increase the code size of Intl.js too much.
• The Default Unicode Collation Element Table is huge, even after compression, and converting to a native JavaScript object would probably make it slightly larger. Server-side JavaScript environments will soon already support Intl.Collator, and we can't really expect client environments to download this data.

There are some local environments where it might be useful, such as a Smart TV platform, desktop widget or something, but String.prototype.localeCompare is probably good enough in those platforms and the gain from an implementation just wouldn't be worth it.

Compatibility

Intl.js is designed to be compatible with ECMAScript 3.1 environments in order to follow the specification as closely as possible. However, some consideration is given to legacy (ES3) environments, and the goal of this project is to at least provide a working, albeit non-compliant implementation where ES5 methods are unavailable.

Locale Data

The main Intl.js file contains no locale data itself. Instead, the data should be provided, parsed into a JavaScript object, using the Intl.__addLocaleData() method.

Intl.js uses the Unicode CLDR locale data, as recommended by the specification. The data is available in JSON format, or JSONP format in the locale-data folder. This has been converted from CLDR version 23.1 using the script and config file in the tools folder.

Collation data isn't currently present since the Intl.Collator implementation isn't finished.